The tweet had been active on Trump’s account without comment or clarification for two hours at time of writing. It had been retweeted 61,000 times and received more than 75,000 favourites, and climbing. That it had not been immediately deleted was confusing to users, who leapt to speculate what, exactly, Trump might have meant. The Merriam-Webster dictionary, which has a track record of fact-checking Trump’s tweets and neologisms on Twitter, decided to sit this one out.

Others suggested the tweet had taken the heat off US comedian Kathy Griffin, who had earlier been under fire for posting a video in which she held a replica of Trump’s severed bloody head.

Kristina Wong, a US comedian, observed that the domain Covfefe.com had been promptly snapped up.

Trump has been known to tweet on both Android and Apple devices in the past, but the “covfefe” tweet had been sent from the Twitter app on an iPhone.

The news site Axios had reported on Thursday that the president’s current device was an iPhone with only one app: Twitter.

It cited anonymous White House officials who said that limiting screen time was key to “forcing a more disciplined President Trump”, as witnessed on his overseas tour:

In Trump’s case, it’s curtailing his time watching TV and banging out tweets on his iPhone. Trump himself has been pushing staff to give him more free time. But staff does everything it can to load up his schedule to keep him from getting worked up watching cable coverage, which often precipitates his tweets. It has worked well overseas so far.